Process of coating car-bodies.



MILTON E. MGDONNELL, 0 .AIJ'I'OONA, PENNSYLVANIA.

rnoc'nss or comma CAR-BODIES.

No Drawing.

To all whom it may concern Be it known that I, MILTON E. MCDON- NELL, a citizen of the United States, residing at Altoona, in the county of Blalr and State of Pennsylvania, have invented certain new and useful Improvements in Processes of Coating Car-Bodies; and I I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to a process for painting and finishing railway cars, especially passenger coaches, and has for its object to provide a method which will accomplish this purpose in less time and more efficiently than has been heretofore possible.

With these and other objects in view, the invention consists in the novel steps and combinations of steps more fully hereinafter disclosed and particularly pointed out in the claims.

In carrying out the process, the car bodies are first given a priming coat, which is preferably devoid of any artificial drier. This coat is, or may be, applied in the usual way, and the car is then passed into a drying oven where it is subjected to a temperature of say 250 F., for about three hours. At the end of this time, it is found that this first coat is sufliciently dry to receive the second coat. Thisrsecond coat is somewhat in the nature of a glaze, and is generally applied with a knifeat the, uneven places so'as to produce as smooth a surface as possible. The car isthen again moved into the oven and subjected for say three hours to substantially 250 F whereupon the second coat will be found sufliciently dry to receive the third, or surfacing, coat, which is applied to those places which are still more or less uneven, ornot perfectly smooth, and the car is still further subjected in the oven to a temperature of say 250 F. and for a period of about three hours. In like manner, as many additional coats may be applied as are found necessary to produce the desired smooth or suitable surface. After a covering of sufficient thickness is thus obtained over the entire car, the surface is then rubbed smooth, or polished, when thecolors are applied in the usual way and likewise subjected to the Specification of Letters Patent.

. Patented Aug. 31, 1915.

Application filed February 20, 1913. Serial No. 749,713.

above. Any gilt lettering, or ornamentation that it is desired, may be applied immediately before the varnish coat, and likewise suitably dried. After the colors and ornamentations are finished, the car may be varnished on both the interior and exterior, whereupon it is again moved into the oven and subjected to a temperature beginning at say 125 F., and then gradually raised up to 150 F. during a period of say about three hours. After two or three coats of varnish are thus applied and subjected to heat treatment, the interior of the car may be rubbed to give it the desired dull finish.

In carrying out the process, any material quantity of drier, or like substance, is omitted in all the coats of paint, and by this omission, most important. results are attained, which will be readily appreciated from the following :-In painting small metallic objects, such as automobile parts, wherein the paint is passed through a drying room and artificially dried, the expansion and contraction of the parts through the changes of temperature, is so small that no serious cracking, or other destructive action upon the coating, is encountered. But, when it comes to painting large or long objects, such as the body of a passenger car, for example, the contractions and expansions might in some cases amount to say as much as an inch, an inch and a half,

or almost two inches, and when successive coats of paint containing a drier, are applied to such large objects and then subjected to a hot room in order to artificially dry the same, these said coats will be checked (@cracked, and otherwise injured to such an extent as to make the drying process wholly impractical. This destructive action is further intensified by the fact that the said driers continue to act and in-- jure the covering even after the coating of paint is thus dried. On the other hand, if these successive coats are applied without a substantial quantity of a drier, or with none at all, and then artificially dried, as above disclosed, all crackin s, checkings, etc., are avoided. This constitutes an important feature of the present process. In other words, this process produces a coat ing on the body of the car which is free subjected to higher temperatures than it 'Msame temperature and for the same time, as will ever be again in practice, and which,

of course, has been subjected to greater strains due to expansions and contractions,

than it will ever meet with in use. It, therefore, results that the coating of this process 5 will last much longer and preserve a better appearance than would be possible with the old coatings.

In addition to the above, the entire time consumed in painting and finishing cars by this method, is only about one-half as long as the time required by the old method. Further, it sometimes happens that for special reasons it is highly desirable to finish a car in a very short time, and. by the old methods, since it requires such very long time to air \dry them, Sunday work and night work is seldom of any use. By this method,on the other hand, the various coats Y can be dried in a few hours, and therefore Sunday and night work can be put on the cars and the whole job finished in a very much less time than it is possible by the old method. Again, in the ordinary process of painting and air drying, linseed oil is generally employed, and although this same oil may be employed with the present process, yet at the same time, it is preferred to add. a vsmall quantity of China Wood oil, say about 20%, but these proportions may be increased or decreased, without departing from the spirit of this invention. It is also desirable to subject these oils toa boilingaction to give them about the consistency' of varnish before adding the pigments for painting. It has been further found of advantage to employ more oil in the priming, or first, coat, than in the succeeding coats, because an elastic coat is desired, which will be non-porous and thoroughly not be liable to crack under the severe expansion and contraction strains.

An additional important feature of this invention will be readily appreciated when it is said :-In the old process, a short oil varnish is employed'on the interior of the car while on the exterior of the car, there is employed a long oil varnish. But the use ofthese difi'erent varnishes is objectionable.

The one cannot be substituted for the other,

because the exterior varnish does not dry sufficiently hard to permit the rubbing to which the interior varnish is subjected, and

the interior varnish cannot apply to the exterior, because it will not stand the weather conditions. By this process, on the other hand, a long oil varnish, known to the trade as an exterlor finishing varnish, can be used on both the interior and exterior of the car, because after receiving the heat ta'eatment above disclosed, this said varnish will be sufficiently hard on the interior to withstand he rubbing above referred to. By a long oil varnish, I mean one having sayfrom 30 95 to40 gallons protect the metal, as well as one which will of oil to 100 pounds of gum,

and by a short oil varnish, I mean one having say about 10 gallons of oil to 100 pounds of gum.

It is obvious that those" skilled in the art may vary the above procedure Withoutdeparting from the spirit of the invention, and therefore, it is notdesired to limit the invention to the above disclosure, except as may be required by the claims.

.What is claimed is 2- 1. The process of finishin metal car bodies which consists in app ying successive coatings substantially devoid of artificial drying materials to said bodies; subjecting each coat to a temperature of substantially 250 F. for a period sufficient to dry the same before applying the succeeding coat; coating said bodies inside and out with a long oil varnish; and subjecting said varnish coat to an artificial temperature above 120 F. for a period sufficient to dry the same, substantially as described.

2. The process of finishing metal car bodies, which consists in applying successive coatings devoid of artificial drying mate rials to said bodies; subjecting each coat to a temperature of substantially 250 F.

for a period of substantially three hours before applying a succeeding coat; applying successive coatings of the same varnish inside and out; and subjecting each varnish coat to a temperature substantially beginning at 125 F. and ending at a temperature of substantially 150 F. for a period sumcient to artificially dry said varnish, sub stantially as described.

3. The process of finishing metal car bod ies, which consists in applying successive coats ofpaint devoid of artificial drying ma terials and of varnish to said bodies; and artificially baking on each of said coats before a succeeding coat is applied, substantially as described.

4. The process of finishing a metal car body which consists in applying a coating of paint substantially devoid of artificial drying materials to said-body; subjecting said coating to a temperature higher than that at which paint containing artificial drying material would deteriorate; finishing said coating inside and out with a long oil varnish; and subjecting said varnish coating to a temperature above-125 F., whereby the said coats of paint and varnish are artificially dried, substantially as described. 5. The process of finishing metal car bodies, which consists in applying one or more coatlngs of paint substantially devoid of artificial drying materials to said bodies, and sub ecting the car body so coated to a temperature of substantially 250 F. for asufiicient period to dry. the same,- substantially as described.

6. The method of painting a metal car body preliminary to varnishing it, which consists in applying to the car successive coats of aint includmgaprimin coat, such coats o paint being substantia 1y devoid 5 of artificial driers, and after applying each coat baking the same on the car body, substantially as described.

In testimony whereof, I afiix my signature, in presence of two witnesses.

MILTON E. MQDONNELL.

Witnesses:

GRACE S. HARKNEBS, Wnmm G. Smma 

